Colour Theory

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Colour Theory
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Colour Theories

• Subtractive Theory
• The subtractive, or pigment theory deals with how
  white light is absorbed and reflected off of
  colored surfaces.
• Additive Theory
• The Additive, or light theory deals with radiated
  and filtered light.

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Subtractive Theory

• Black absorbs most light
• White reflects most light
• Coloured Pigments absorb light and reflect only
  the frequency of the pigment colour.
• All colours other than the pigment colours are
  absorbed so this is called subtractive colour
  theory.
• The primary colours in Subtractive Theory are
• Cyan ( C )
• Magenta ( M )
• Yellow ( Y )
• Black ( K )
• Subtractive or Pigment Theory is used in printing
  and painting.

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Additive Theory

• Black radiates no light
• White (sun) radiates all light
• Video is the process of capturing and radiating
  light, therefore it uses Additive (Light) Theory
  not Subtractive (Pigment) Theory.
• The primary colours in Additive Theory are
• Red ( R )
• Green ( G )
• Blue ( B )
• The primary colours add together to make white
• Light Theory is also called Additive Theory.
• Light Theory is used in Television, theater
  lighting, computer monitors, and video production.

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The Visible Spectrum
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The Colour Wheel
If the ends of the spectrum are bent around a
colour wheel is formed
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The Colour Wheel

• Colours on the wheel can be described using three
  parameters
• Hue degrees from 0 to 360
• Saturation brightness or dullness
• Value lightness or darkness
• (As suggested by Henry Albert Munsell in A Colour
  Notation, 1905)

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The Colour Tree by American artist Henry Albert
Munsell fromA Colour Notation, 1905.
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The Colour Wheel Hue

• Hue or Spectral Colour is represented as an
  angle.
• Primary Colours
• 0 Red
• 120 Green
• 240 Blue
• Secondary Colours
• 60 Yellow
• 180 Cyan
• 300 Magenta

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The Colour Wheel Saturation

• Saturation or Chroma is the intensity of a
  colour.
• A highly saturated colour is bright and appears
  closer to the edge of the wheel.
• A more unsaturated colour is dull.
• A colour with no saturation is achromatic or in
  the grey scale.

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The Colour Wheel Value

• "the quality by which we distinguish a light
  color from a dark one."
• Albert Henry Munsell
• A Colour Notation 1905
• Value represents the luminescent contrast value
  between black and white

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The Colour Wheel Value
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The Colour Wheel Value
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The Colour Wheel 3d

• Three parameters to describe a colour Hue
  Chroma Value

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Tone Shade Tint
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Colour Pickers

• HSB, HLS, HSV
• RGB
• CMYK
• Others
• Crayon
• Lab
• PANTONE

Munsells notation wheel
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Colour Pickers HSB, HLS, HSV

• HSV
• Hue
• Saturation
• Value
• HSB (Same as HSV)
• Hue
• Saturation
• Brightness
• HLS
• Hue
• Lightness
• Saturation

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Colour Pickers RGB, CMYK

• RGB
• Red
• Green
• Blue
• Used in Video and Computer graphics
• 3 Values in or between
• 0-255
• CMYK
• Cyan
• Magenta
• Yellow
• K Black
• Used for printing

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Colour Pickers Crayon, PANTONE

• Crayon
• Easy to use
• Pantone Colour Matching System
• Standard for the printing industry

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Colour Pickers Lab

• L,a,b Colour opposition correlates
• L Lightness (0 White, 100 Black)
• a to -a Red to Green
• b to -b Yellow to Blue

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Colour Pickers Bit Depth

• Each colour is described by 3 values, each with a
  possible range of 0 to 255.
• 256 x 256 x 256 16,777,216 possible colours
• 224 16,777,216 24 bit colour

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Colour SchemesSystematic ways of selecting
colours

• Monochromatic
• Complimentary
• Analogous
• Warm
• Cool
• Achromatic
• Chromatic Grays

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Colour Schemes Monochromatic

• Monochromatic
• One Hue many values of Tint and Shade

Artist Marc Chagall Title Les Amants Sur Le Toit
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Colour Schemes Complimentary

• Complimentary Colours that are opposite on the
  wheel. High Contrast

Artist Paul Cezanne Title La Montage Saint
Victoire Year 1886-88
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Colour Schemes Analogous

• Analogous A selection of colours that are
  adjacent. Minimal contrast

Artist Vincent van Gogh Title The Iris Year
1889
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Colour Schemes Warm

• Warm First half of the wheel give warmer
  colours. The colours of fire.

Artist Jan Vermee Title Girl Asleep at a Table
Year 1657
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Colour Schemes Cool
Artist Pablo Picasso Title Femme Allongée
Lisant Year 1939

• Cool Second half of the wheel gives cooler
  colours

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Colour SchemesAchromatic, Chromatic Grays
Achromatic Black and white with all the grays
in-between.
Chromatic Grays Also called neutral relief. Dull
colours, low contrast.
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Colour Theory

• Colour Theories
• Subtractive (ink)
• Additive (video)
• The Colour Wheel
• Colour Pickers
• HSB, RGB, CMYK
• Colour Schemes
• Monochromatic
• Analogous
• Complimentary
• Warm, Cool